The present disclosure relates to digital circuits and related circuit structures.
The exponential growth of digital computing power, demanded by modern applications, has been realized thanks to Moore's Law: the doubling of the number of transistors available per unit area approximately every 18 months, rendered possible by the incessant scale-down of the transistor size. To prevent the amount of power consumption from growing explosively, system voltages are consistently decreasing.
When the digital circuit is operated at a low system voltage, new challenges appear. In particular, the effect of leakage current, sometimes called “off current,” manifests itself more prominently under low system voltage. At the same time, it is desirable to maintain the amount of operating current, sometimes called “on current,” to achieve certain performance criteria. Therefore, it is desirable to control the amount of leakage current to the maximum extent possible without sacrificing too much on the operating current.